Fyi.
http://www.nytimes.com/2012/06/05/science/skull-analysis-charts-the-changes-from-dinosaurs-to-birds.html
SIDE EFFECTS: In Skull Analysis, Charting the Path From T. Rex to Falcon
By JAMES GORMAN 11:42 AM ET
In the course of birds’ evolution from dinosaurs, it appears that their skulls pulled a Peter Pan and stopped growing up.
"....Some subtle genetic change slowed or stopped the development of the skull as a bird embryo grew in the shell and after hatching. The body kept on growing and changing proportions, but the skull changed only in size. It did not change in shape.
As a result, the skulls of birds look like those of baby dinosaurs. "